Drawing of slivers



, Filed May 19, 1950 DRAWING 0F SLIVERS 1N VENTOR RUDOLF KERN WERNERPAUEN BY uy/ ATTORNEY United States Patent DRAWING OF SLIVERS RudolfKern, Bonn, and Werner Pauen, Dusseldorf, Germany Application May 19,1950, Serial No. 177,468

Claims priority, application Germany May 20, 1949 Claims. (Cl. 19-131)This invention relates to new and useful improvements in the drawing ofslivers. More particularly the invention concerns an improvement in thedrawing mechanism of pre-spinning and fine spinning devices.

One object of the invention is among others an 1mproved draft in thedrawing of fiber slivers. This and further objects of the invention willbe apparent from the following description.

In accordance with the invention all fibers of a sliver are moved by afiber securing transport between the entering or back roll and thedelivery or front roll of a drawing machine for a distance therebetweenof at least half the length and preferably the entire length of thelargest fiber in the sliver and at a lesser speed than thecircumferential speed of said front roll, the fibers being held sotightly by said transport that fibers above predetermined length aremoved by the front roll only when being gripped thereby while anyshorter fibers are so moved only after having completely left saidtransport.

Within the preferred embodiment of the invention therefore the transportextends practically the entire distance between the back roll and thefront roll and passes the fibers of the sliver to within the closestproximity of the front or delivery roll.

The rate of advance of the transport is substantially equal that of theback roll or preferably somewhat higher so that the sliver may be passedon to the transport under light tension.

When reference is made herein to the expression sliver or where suchsimilar term is used there is intended to be designated thereby anyconglomerate of fibers as it is conventionally subjected to a drawingoperation in the pre-treatment of fibers for the spinning thereof intoyarn and including card slivers, combed slivers, gilled slivers, rovingand slubbing.

This positive fiber transport is obtained in accordance with theinvention by way of a pulling-through drawing arrangement in that thereis provided between the back roll and front roll a surface continuouslymoving in the direction of the movement of the sliver such as an endlesstape or an appropriately large roll, the surface of which possesses sucha grip for the fibers that the same are retained in position on the rollagainst the force of a pull exerted upon them by other fibers which aredrawn by the front roll.

The transport is preferably so arranged between the front and back rollsthat the fibers pass along a portion of the circumference of theserolls. This makes it possible to provide for a particularly shortpassage from the transport on to the front roll. When treating combedslivers this distance between transport and front roll may be madeadvantageously shorter than the length of the combed out fibers.

The surface of the roll or endless tape may be suitably roughened forthe purpose of imparting thereto the required gripping action such as byproviding the same with flutes, teeth, pins, projections or similarexpedients. It is in many cases desirable to press the sliver on to oragainst the surface of the transport such as by a dabbing roll or bysmall straps or thongs. These last-mentioned expedients for pressing thesliver against the transport may be driven by the surface on to oragainst which the sliver is pressed.

When practicing the invention it is possible without difiiculty toobtain drafts, i. e., ratios of delivery from the front roll to speed ofentering of sliver on the back ice roll which exceed twice the draftsobtainable with currently practiced drawing methods. While ordinaryfinishers today permit drafts of a maximum of 4.5, it is possible inaccordance with the invention to obtain without difficulty thirty timesthe draft. It is thus possible to materially reduce the number ofdrawing devices or machines and thus the number of spinning machines.The advantages of the invention are applicable to all drawing devices ormachines of all types, i. e., regardless of whether they are of thepre-spinning or fine-spinning stage.

The invention is particularly applicable to long staple fibers that maybe also used in connection with short staple fibers.

Some of the modern drawing devices or machines provide supports forguiding short fibers which float between the back and front rollerpairs. These are usually in the form of a pair of pulling-throughcylinders which permit the longer fibers that are in gripping contactwith the front or delivery roll to be passed. through while the shorterfibers are stopped by sluice-type funnel. Even with such type drawingdevices only relatively low drafts are obtainable since the short fiberswhich are embedded within the long fibers or which rest upon the latterwill be pulled along in the free interspaces between the cylinder palts.

Higher drafts are obtainable with the previously known drawing machinesor devices of the strap or thong or double strap type in which thefibers are transported on or between straps or thongs of leather orsimilar material being thereby retarded in their movement towards thepair of delivery rolls establishing in this manner a speed differentialbetween the transport on or between the straps or thongs and thegripping delivery roller pairs. The straps or thongs, however, do notprevent that the long fibers which are gripped by the front or deliveryroll will pull the shorter fibers along. For this reason, therefore,strap or thong drawing devices do not give drafts which are appreciablyabove other conventionally obtained draft values. Furthermore, thesestrap or thong drawing devices have found practical application only forshort staple fibers while the invention is particularly designed for useWith long staple fibers.

Another spinning method for combed slivers with a maximum of mm. staplelength has become known. An increased draft is obtained in this methodby tearing the fibers above 80 mm. length between drawing rolls whichare under high load. This method has the disadvantage that the valuablelong fibers are destroyed, that its application is only possible forcertain raw materials and that the number of doublings is restrictedduring the preparation thus also restricting the mixing and uniformityof the slivers.

The invention is free from the above-mentioned disadvantages anddrawbacks. It is particularly useful for long staple fibers andspecially designed for saving the long fibers.

The invention is illustrated by way of exemplification in the drawings,in which Fig. 1 is a diagrammatic side view of a drawing frame inaccordance with the invention; and

Figs. 2, 3, and 4 are embodiments of rollers of the drawing frame shownin Fig. 1.

In the drawing frame as illustrated in Fig. l, the sliver 11 is drawn inby the feed roller pair 12-13. The upper roller 12 of the feed rollerpair is covered with leather or the like in the conventional manner,while the lower roller 13 is a conventionally fluted roller. Sliver 11is delivered by the front or delivery roll pair 14-15, which isconstructed similar to the feed roller pair 12-13, with an appreciablygreater speed than it is drawn into the device by the feed roller pair.Delivery roll 14 may be weighted or not, as may be appropriate ordesired in accordance with the particular spinning stage. A guide roll18 having a substantially larger diameter than either of the deliveryrolls is positioned between the feed roller and the delivery roll pairadjacent to the delivery roll, so that the sliver will pass over atleast /3 of its circumference. The size of this roller should be suchthat at least A2 and preferably a length of sliver equal to at least themaximum fiber length is in contact with this guide roll. The

surface of this guide roll is provided with gripping or fiber-holdingmeans.

A strap or throng 19, guided in frame 20 by rollers 21, 22, and 23 ispositioned for pressing the sliver in contact with the guide roll. Theframe 20 is pivotable relative to pivot post 24, and carries slide track25, provided with slide weight 26, which may be secured in position bywing nut 27. Strap or throng 19 can be thus placed upon roll 18 bypivoting the frame around pivot post 24 and will then be pressed againstthe surface of roll 18, adapting itself to the surface contours thereof.The same is then transported by reason of its frictional engagement withroll 18. The pressure may be shifted to intake or delivery by changingthe position of the sliding weight.

The guide member 23 is constituted as a guide needle or pin of suchsmall diameter that the strap or throng 19 presses the sliver againstroll 18 up to immediately preceding its arrival on the front or deliveryroll 14. Guide pin 23 may be adjusted horizontally as well asvertically.

The guide roll 18, the guide member 23, and the delivery roll pair 1415are so positioned, as shown, that the sliver will leave the guide roll18 at an angle approximately tangential thereto at the point at which itis pressed against the drive roll by the strap or throng 19 at the guidemember 23. The guide member 23 has a radius of curvature which is muchsmaller than the radius of curvature of the delivery roll.

The guide roll should rotate at substantially the same peripheral speedas the feed roller pair, the peripheral speed of the guide roll shouldnever be in excess of 20% and preferably at the most higher than that ofthe feed roll 12.

The particular manner in which an increased gripping action may beobtained for the surface of the sliver transport in accordance with theinvention depends upon conditions and particularly upon the type offibers, material of the transport surface and its speed of travel and incertain cases also upon the devices or expedients used for pressing thesliver against the transporting surface. Thus roll 18 may be made ofmetal, wood, pressure molded resins or similar materials, and itssurface may be provided with projections for carrying the fibers alongor, for instance, with flutes, channels, netting, ropes, etc. or withany other suitable roughening of any type well known in the art. Fig. 2shows a deeply fluted roll 18a While Fig. 3 illustrates a roll 18bcomposed of multiple circular sections 180 and intermediate separatingrings 18d.

Fig. 4 shows a roll 18e which is provided with a coating of projectinghard granules, such as, for instance, an emery sleeve. Rolls as shown inFig. 4 are in general particularly suitable for fine-spinning machines,while for coarser material preparing machines and heavier slivers, asfor instance, combed slivers, there may be either used coarse grainedcoatings or relatively coarse flutes as shown in Figs. 2 and 3, and intowhich individual fiber strands will be pulled. When using an arrangementof a roll according to Fig. 1, the distance which the sliver traversesbetween its take-off from roll 18 and its passage onto delivery or frontroll 14 may be varied to almost any desired shortness. It is alsopossible to position the back roll 12 so close to roll 18 that thesliver 11 is supported practically throughout its entire travel throughthe device. It is thus possible with such an arrangement to place thefront or delivery roll 14 so close to the roll 18 that practically allof the fibers of sliver 11 are held in position on roll 18 until theyare individually gripped by roll 14.

For the purpose of reguating the draft and the speed of rotation of thefront or delivery rolls there is provided, in addition to the gear trainsituated between the front and back rollers or back roller drives, avariable transmission, preferably of the continuous (non-stepped) type.The drive of roll 18 is preferably obtained from the same motive poweras the drive for the back rollers and is then preferably obtained by wayof a gear train through which a certain over-drive if desired of thesliver-gripping transport roll may be obtained relative the back roll.As already previously set forth, it is of advantage that the grippingsurface possesses a certain overspeed relative the back roll so that thesliver may be passed onto the transport surface with a certain tension.

In applying this procedure the advantages may be considerably increased.If, for instance, in the end-passages of worsted yarn preparationdrawing devices in accordance with the invention were used in only twosuccessive machines with the thirty times draft in each, there would beobtained after the second passage a total draft of 30 30=900, while itwas up to now only possible to obtain a total draft of at the most 4.54.5=20. A total draft of 900 is so high that the sliver even withmultiple doubling cannot be spun any more without a further finishing.Inasmuch as at least a increase in draft is obtained when using theinvention in connection with ring spinning, it is possible when applyingthe invention to short-cut several preparation and sliver thinningpassages and to thus reduce the entire spinning procedure by at least50% and to correspondingly reduce the number of spinning machines. Thus,for instance, an ordinary ring spinning machine was altered by providingthe same with drawing devices in accordance with this invention. Fortyto sixty times the draft were obtained and instead of spinning the yarnfrom the eighth preparation step, it was possible to take the same fromthe fifth to sixth steps.

The fullest utilization of the high drafts obtainable in accordance withthe invention is not so much limited by the technical factors involvedin the speed differential between front and back rolls but rather by thefact that currently available preparation slivers are not suflicientlyuniform and have to be made uniform by doubling. The use of relativelyhigh drafts is furthermore limited in those cases in which mixtures ofdifferent fibers are desired or required.

We claim:

1. Drawing device for spinning machines comprising feed roll means,delivery roll means positioned in spaced relation and substantiallyparallel to said feed roll means, a guide roll having a substantiallylarger diameter than said delivery roll means positioned between saidfeed roll means and delivery roll means adjacent said delivery rollmeans for contact with a sliver being passed through said feed rollmeans and delivery roll means over a substantial portion of itscircumference, a flexible belt guided around at least two spaced-apartguide members positioned for pressing said sliver in contact with saidguide roll, one of said guide members being a curved guide member havinga substantially smaller radius of curvature than said delivery rollmeans and being positioned adjacent said guide roll and delivery rollmeans in the space defined therebetween, defining the run-ofi point ofthe sliver from the guide roll to the delivery roll means, and means forimparting rotary motion to said feed roll means and said guide roll atsubstantially the same peripheral speed and to said delivery roll meansat a substantially greater peripheral speed.

2. Drawing device according to claim 1, in which said flexible belt ispositioned for contact with the upper portion of the surface of saidguide roll and in which said guide roll is dimensioned and positionedfor surface contact with a sliver being passed through said feed rollmeans and delivery roll means over at least one-third of itscircumference.

3. Drawing device according to claim 1, in which said curved guidemember is adjustably positioned for varying the run-off point of thesliver from the guide roll to the delivery roll means.

4. Drawing device according to claim 1, in which said feed roll means ispositioned adjacent said guide roll.

5. Drawing device according to claim 1, in which said flexible belt ismounted on roll means positioned in a frame having a weight movablyslidable between said feed roll means and delivery roll means.

6. Drawing device according to claim 1, in which said flexible belt isguided on roll means mounted in a hinged frame.

7. Drawing device according to claim 6, in which said hinged frame has aweight movably slidable between said feed roll means and delivery rollmeans.

8. Drawing device according to claim 1, in which the surface of saidguide roll is of suflicient roughness to hold fast against transverseand longitudinal motion of any fiber of the sliver in surface contacttherewith.

9. Drawing device according to claim 1, in which said guide roll hasmultiple projections extending from the surface thereof.

10. Drawing device according to claim 1, in which said flexible belt isguided around three of said spacedapart guide members positioned forpressing said sliver in contact with said guide roll.

(References on following page) References Cited in the file of thispatent 2,497,511

UNITED STATES PATENTS 339,329 Schiefner Apr. 6, 1886 19,984 391,781Cheyne Oct. 30, 1888 5 428,738 1,433,529 Butler Oct. 31, 1922 672,9571,545,803 Vanni July 14, 1925 6 Neisler Feb. 14, 1950 FOREIGN PATENTSGreat Britain of 1910 Germany May 11, 1926 France Sept. 24, 1929

